The fundamental uncertainty that accompanies innovation and transformation processes has influenced a growing body of literature on adaptive, explorative and reflexive planning. Such notions take stock of the complex interdependence in technological, social and spatial development. The article explores notions of reflexivity in urban planning and expands three dimensions with respect to the ongoing mobility transition: Openness and flexibility; learning and exploration; and embedding of initiatives. In this context, the article further reviews real-world laboratories as a format to structure learning processes and transdisciplinary collaboration for alternative mobility futures. In the wake of a rapidly growing new mobility sector in cities, aspirations of problem-solving through technology prevail. Yet urban planners and policy makers are challenged to evaluate opportunities and risks in relation to existing urban development goals. Reflexive strategies encourage long-term thinking, anticipation of unintended consequences and short-term explorations. A systematic integration of reflexivity can enable urban planners to intentionally guide change processes, while also facilitating the agency of others.